Biodiversity: the level of different traits within life. Biological diversity. Includes habitat, species, and genetic. 

Habitat Diversity: different habitats and niches per area used by many species. The more variety within habitats, the more different species you get support. 

Species Diversity: Number of species (richness) and number of organisms per species (evenness) per unit area. The more species diversity, the more different types of genes

Genetic Diversity: The variety of genes and combinations of all the population

Endemic: native in only one area. Particularly bad when an endemic species goes extinct, as they do not exist anywhere else in the world. 

Quantifying Biodiversity

Biotic Index: Simpson’s is the most common where species richness and evenness are used to quantify. The higher, the more biodiversity and the more stability (less disturbances)

Why protect diversity? Aesthetic, economic, health, cultural, moral, etc. reasons. We get goods and services from our earth. 

Oxygen, water, foods, medicine, space, etc. 

Biodiversity Hotspot: an area with particularly high levels of biodiversity and is under threat. Problematically many of these areas are near industrialized areas. 

Measures of biodiversity help identify which areas need to be protected. 

Equator; near water; 

Most biodiverse areas: US, China, Mexico, Brazil, etc. 

Origins of Biodiversity

Natural Selection: natural process by which a species evolves (changes) over time. Reproductive success comes based on genetic traits

Fitness: how likely it’s going to reproduce or ability

4 steps of natural selection:

NATURAL SELECTION: VCAS - vultures cook at sky

1. Variation - some sort of mutation leads to different traits within the same species

2. Competition - inter/intraspecific

3. Adaptation - beneficial adaptations will be passed on, while less beneficial adaptations die out

4. Selection - change in allele frequency

Individuals cannot evolve

Type of Selection

Directional: pressure is put on the species to shift in only one direction. The trait may go from big feet to little feet, or vice versa. 

Stabilizing: Extremes are no longer useful to survive, and start being pushed toward the middle. 

Disruptive: middle traits are no long useful to survive, thus the pressure leads to a split within the curve to the extremes

Advantages of specialization: you get really good at what you do and thus you’ll always win at that very specific task

Disadvantages of specialization: you can’t do anything else. Also get limited to one food basically, and if that thing dies they’re going with it. 

Cheetahs! Very weak but very fast. Can only eat gazelles. 

Microevolution: change in genetic makeup of a species rather quickly

5 ways it occurs:

1. Shrink of population/DRIFT→ genetic drift where population gradually changes over time as a result of random change

   1. Slowly drifting away from the sea shore

2. Mating (non random) - animals do not choose mates completely randomly, they choose based on desirable traits that will eventually be passed down

3. Mutation - affects frequency

4. Immigration/FLOW - gene flow

5. Natural selection - actual adaptations

Genetic Drift:

Bottleneck effect: reduction of population leads to reduced genetic variation

Founder effect: the effect of descending from a small number of colonizing individuals lads to a change in composition. Also applies to bottlenecks. 

Speciation: the way species develop. How does one group become another group? 

Usually through isolation or some sort of changing circumstance

Plate tectonics and how they contribute:

Number of species: 

Rough ballpark of 9-10 million 

2 million have been identified

Only _% have been cataloged due to isolation and some species going extinct before we can even detail them. 

Background Extinction & Mass Extinction

Background extinction rate: 10-100 species go extinct per year.

Mass extinction: we’ve pushed this number much higher, to catastrophic levels, representing a mass extinction (anything higher than the bg rate)

Non-human caused extinctions

• Volcanic events

• Ocean temperature changes

• Sea level changes

• Meteor

• Glaciations

• Global climate changes

6th Mass Extinction

What is it? Why is this happening?

Some ecologists believe we are currently within the 6th Mass Extinction, happening due to our unsustainable actions. For the first time it is humans causing the extinction, not something in nature. 

Characteristics of species prone to extinction

• Low populations in general

• Low genetic diversity

• Endemic to an area

• K-strategists (don’t reproduce very fast)

• Specialized animals

• Low population density

• Appealing human traits (ivory, horns, pelts)

Red List (IUCN)

Aims to detail all the species in the world. Used as decision making and data bank for many groups. Hope to influence, encourage, etc. → conservation

Statuses (list most important) Extinct, extinct in wild, critically endangered, endangered, threatened, vulnerable

Anthropogenic causes of biodiversity loss - habitat loss

Agriculture

Natural hazards

Disease spread

Habitat loss

Invasive species

Population

Pollution 

Overconsumption

AND HIPPO 🔼

Habitat Loss and Fragmentation (breaking into smaller pieces)

Edge Effect - the less round and more jagged the habitat is, the more edge there is, which is closer to the outside world. Results in new predation and invasive species that live in the ecotone New species introduced, new diseases, predators, etc. Some animals cannot survive in the center. 

Ecoture - boundary between two areas. Transition area. 

Rainforest destruction, causes (4)

1. Cattle ranching

2. Logging

3. Slash and burn

4. Plantations

Why should we care? One of our most biodiverse areas. Genetic diversity comes from this area, and crops become monocultures → vulnerable to blight. 

Medicines come from the rainforest. 

Pollution

Intentionally vs unintentionally - accidentally have trash blow away or dumping sewage into the pipes. 

Climate change - pollution alters composition of soil, water, etc. Greenhouse gasses within the atmosphere lead to climate changes - and these are happening so fast animals don’t have the time to adapt. 

Overconsumption

Using excessive resources - standards of live increase, society consumes more and more

Larger homes use more electricity, water, food, 

Technology leads to more use of resources (chainsaws, sonar, scoped rifles, etc.)

Exploitation of Animals 

Illegal animal trade is lucrative. Parts can be worth 100k on the black market for pelts, teeth, etc. Usually for something entirely frivolous (wah live forever from totoaba!)

Positive feedback loop: reduction of supply → smaller market → less supply → more valuable → increased demand → lower supply → repeat

Invasive Species

Characteristics - small, reproduce quickly, no native predators, causing great decimation to the environment it’s invaded

Types of removal (4)

1. Mechanical 

2. Biological

3. Chemical

4. Genetic

Conservation of Biodiversity

Reasons to protect it (5) Economic, moral, cultural/social, aesthetic, ecologic

How are we preserving it? 

CITES - Convention on International Trade in Endangered Species from the United Nations

Strengths - protects specific species, regulates trade, punitive measures detailed

Weaknesses - not all countries are signees, noncompliance is rampant, and each country must fund it themselves, not all species receive the same attention

Conservation Legislation in US

Endangered Species Act in US (1974)

Protects trade in products from endangered species, prevents destruction of endangered species and habitat. Very successful

NGOS vs GOs (strengths and weaknesses)

GO Approach - non inflammatory use of media

Strengths: has more financial resources. Enforceability.

Weaknesses: slow response due to diplomatic and political constraints. Cannot be inflammatory and must be careful about other countries. 

IUCN, UN Environmental Program

NGO Approach - 

Strengths: can be more inflammatory/appeal to emotion, unaffected by political constraints

Weaknesses: generally less funding and has no legal power. 

Habitat Conservation vs Species Conservation

Habitat Conservation: 

Strengths: ensures land and aquatic areas are available, more ecologically sound

Weaknesses: difficult to connect emotionally

Species Conservation: bring endangered species into captivity then selectively breed → release to adjust. Successful with whooping cranes and California condor but more often leaves them stuck in captivity. 

Strengths: less money, requires less education, branding 💪

Weaknesses: not as effective as habitat conservation, how do you choose which species to save and which to not? 

Zoos (species conservation)

Strengths: Bring into captivity, ensure safety, raises awareness that leads to more donations, educational outreach